A comment left by your mother (who you reluctantly added as a friend) on your Facebook. They are typically lame and/or embarrassing and can often be a source of great entertainment for your friends. Momments are frequently deleted.

"Dude, this is killing me! I got another momment yesterday. I swear she checks my facebook daily."
"She has to stop mommenting or I'm gonna remove her as a friend."

Chad Bronson "SOO WASTEDDD WAT A NIGHTT"
Marcia Bronson "Honey, we should talk about this :("

The kinds of comments that only a mother makes. They are usually a little obtuse and possibly totally obvious.

My mom makes the most obtuse mom-ments sometimes. Like yesterday morning, I was telling her how I was going out with friends and she reached for my arm and said "Now Dear, if you are going out with your friends, you really should change out of your pajamas. Those are pajamas, right? I never can tell the fashion these days."